Using these ideas, we may define (see [1]}) the perverse Leray spectral sequence associated to our fibration \(\pi \colon Y \rightarrow B\)  to be the spectral sequence with \(E_2\) -term
\(E_2^{p,q} := \mathbb {H}^p(B,{\mathfrak {p}}{}{\mathcal {H}}^q(R\pi _*\underline{\mathbb {Q}}_Y)) \Rightarrow H^{p+q}(Y,\mathbb {Q}).\) 
